This invention relates to a process for producing phosphorothioic dichlorides from aldehyde, PCl.sub.3, and sulfur monochloride reactants.
The following process is disclosed in EPO patent application No. 160,344 published Oct. 6, 1985: EQU CCl.sub.3 CHO+PCl.sub.5 .fwdarw.CCl.sub.3 CHClOPCl.sub.4 EQU CCl.sub.3 CHClOPCl.sub.4 +H.sub.2 S.fwdarw.CCl.sub.3 CHClO(S)PCl.sub.2
the sequence of reactions being expressed in terms of desired intermediate and final reaction products only. The same general process is disclosed in East German Pat. No. 123,096 granted Nov. 20, 1976 except that a broader range of aldehydes than chloral (CCl.sub.3 CHO) are used. V. M. Schnell, G. Erfurt, and H. Zinner, J. Prakt. Chemie, 319 (1977) pp. 723-726 also discloses the reaction as follows: ##STR1## wherein R is polyhaloalkyl, disclosing in particular CCl.sub.3 and CHCl.sub.2. One disadvantage of the process disclosed in these publications is the use of H.sub.2 S as a sulfurizing agent, the disadvantage arising from the extreme toxicity of H.sub.2 S, requiring extreme care in transportation, if necessary, and handling. Another disadvantage arises from the need to use PCl.sub.5 which as a solid usually requires the use of elevated temperatures in order to keep this reactant in solution.
G. Schrader discloses in German Patent 1161556 (1964) and in Organic Phosphorus Compounds, 7 (1976), edited by G. Kosolapoff and L. Maier, on page 504, the use of sulfur monochloride as a sulfurizing agent in the following reaction: EQU 3s-BuOPCl.sub.2 +S.sub.2 Cl.sub.2 .fwdarw.2s-BuOP(S)Cl.sub.2 +P(O)Cl.sub.3 +s-BuCl